Extraocular muscle volume reduction in a patient treated with two courses of teprotumumab for thyroid eye disease.

PURPOSE: To report magnetic resonance imaging (MRI) extraocular muscle (EOM) volume analysis in a patient with thyroid eye disease (TED) who was treated with two full courses of teprotumumab.

OBSERVATIONS: An 84-year-old man with TED received two full courses (16/16 infusions) of teprotumumab. At the initial presentation, he had decreased visual acuity, proptosis, and diplopia. Imaging at this time illustrated enlarged EOMs, predominantly on the left side. After his first course of teprotumumab, his symptoms improved. However, he experienced disease reactivation 7 months later. A follow-up MRI revealed reduced EOM volume compared to baseline, though the patient reported recurrent symptoms. A second course of teprotumumab (8/8 infusions) was initiated, leading to clinical improvement. Six months after completion of his second teprotumumab course, a third MRI showed further reduction in EOM volumes compared to both baseline and pre-retreatment imaging.

CONCLUSION

This case demonstrates the potential for continued radiographic and clinical improvement in TED patients after retreatment with teprotumumab. Further studies may clarify the role of EOM volume as a marker for treatment efficacy.